The Westminster Coroner’s Court heard Thursday — on what would have been O’Riordan’s 47th birthday — that she had been drinking heavily before she was found dead Jan. 15 at the Park Lane Hilton hotel, The Guardian reported.

Her alcohol level was 330mg per 100ml of blood — more than four times the legal limit for driving of 80mg, according to the findings.

An autopsy report by Dr. Adam Combe concluded that she drowned as a result of alcohol intoxication. Authorities said after her death that it was not suspicious.

The coroner, Dr. Shirley Radcliffe, said: “There’s no evidence that this was anything other than an accident. There was no intention, this seems to be solely a tragic accident.”

Her mother, Eileen O’Riordan, as well as one of the singer’s brothers and sister-in-law attended the inquest, according to the paper.

A maid found O’Riordan submerged, face up in the bath, during a recording trip ahead of a planned tour. When paramedics arrived, police were performing CPR on her.

O’Riordan, whose distinctive and powerful voice helped fuel The Cranberries’ rapid rise in the early 1990s, had to cancel a tour with the reunited group last year because of a back problem.

Her partner at the time of her death, New York-based DJ and producer Ole Koretsky, said: “The love of my life is gone.”

According to the inquest, evidence also was found of heavy smoking and the of use of prescription drugs, including lorazepam, which is used to treat anxiety.

Five empty bottles of alcohol from the minibar were found, as well as a bottle of champagne.

A report by an American psychiatrist — Dr. Robert Hirschfield, who spoke to her by phone late last year —was read at the inquest.